Fix #62179: Restrict import attribute values to string literals

[sdotson]

Summary

Fixed Issue #62179: Import type attributes were incorrectly accepting arbitrary JavaScript expressions instead of only string literals.

Changes Made:

1. Parser Fix (src/compiler/parser.ts:8447)
   - Changed parseAssignmentExpressionOrHigher() to parseLiteralLikeNode(SyntaxKind.StringLiteral)
   - Now properly restricts import attribute values to string literals only
2. New Test (tests/cases/compiler/importTypeAttributesNonString.ts)
   - Tests that non-string values (functions, numbers, arrays, objects, etc.) are properly rejected
   - Verifies string literals still work correctly
3. Updated Tests
   - Fixed existing tests to reflect the new parser behavior

Fixes issue #62179

[typescript-bot]

This PR doesn't have any linked issues. Please open an issue that references this PR. From there we can discuss and prioritise.

[typescript-bot]

This PR doesn't have any linked issues. Please open an issue that references this PR. From there we can discuss and prioritise.

[Copilot]

Pull Request Overview

This PR fixes issue #62179 by restricting import attribute values to string literals only, preventing arbitrary JavaScript expressions from being used. The parser previously accepted any expression (functions, numbers, arrays, etc.) in import attributes, which violated the ECMAScript specification.

Key changes:

• Modified the parser to only accept string literals as import attribute values
• Added comprehensive test coverage for various invalid expression types
• Updated existing test baselines to reflect the stricter parser behavior

Reviewed Changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/compiler/parser.ts	Changed parser to use parseLiteralLikeNode(SyntaxKind.StringLiteral) instead of parseAssignmentExpressionOrHigher() for import attribute values
tests/cases/compiler/importTypeAttributesNonString.ts	New test file validating rejection of non-string expressions and acceptance of valid string literals
tests/cases/fourslash/organizeImportsAttributes4.ts	Removed test case with numeric attribute value (now invalid)
tests/baselines/reference/importTypeAttributesNonString.*	Baseline files for the new test showing expected errors for invalid attribute values
tests/baselines/reference/importAttributes6(module=).	Updated baselines reflecting changed parser behavior producing syntax errors instead of type errors
tests/baselines/reference/importAssertionNonstring.*	Updated baselines for import assertions with non-string values

[RyanCavanaugh]

The error messages in this test are much worse now

[sdotson]

I think they should be better now. Thank you for the review.

[typescript-bot]

With 6.0 out as the final release vehicle for this codebase, we're closing all PRs that don't fit the merge criteria for post-6.0 patches. If you think this was a mistake and this PR fits the post-6.0 patch criteria, please post to the 6.0 iteration issue with details (specifically, which PR and which patch criteria it satisfies).

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